Photoelectric observations and analysis of the low-amplitude Delta Scuti star 78 Tau

Photoelectric observations carried out over a 6-yr interval in the Johnson V-band were analysed for the component frequencies. Five frequencies were found to be definitely present, of which those four of the highest amplitudes agree with the values recently cited in the literature. Although frequency spacing indicates non-radial oscillations, precise mode identification should await more accurate pulsational calculations and/or spectrum line profile analysis. The five-frequency solution describes the observations to an accuracy of the noise level, though small systematic differences do exist in some cases. Light-time effect due to orbital motion is clearly shown to be present in the photoelectric data and indicates that the source of all the observed oscillations is the primary component. (author)